STAT3 and cancer: Based on studies that IL-6/Stat3 and PD-1/PD-L1 signaling pathways play important roles in cancers [6, 7, 11, 12], of which these molecules obtainable in biopsies before surgery and, TNM staging is not available before surgery, we have tested the hypothesis that cancer-associated signaling molecules may serve as potential markers capable of predicting survival prognosis before surgery among followed-up GC patients.